This slide show was presented ant the Southern California Water Dialog at its April 28, 2010 meeting at Metropolitan Water District Headquarters. Facts and Opinions expressed in the presentation are valid as of that date. Improvements in our state of knowledge and technology may change, over time, some of the conclusions offered.

1. POTABLE REUSE:
When Are We Going to Drink It?
Bahman Sheikh
Bahman.sheikh@gmail.com
April 28, 2010

2. Presentation Outline
• Demand for Water and Supply
• Evolution of Water Recycling
• Direct or Indirect?
• Who Is Drinking Recycled Water?
• Who Failed to Implement Potable Reuse
• Advantages of Potable Reuse
• Energy Use, Cost Comparisons
• Obstacles to Potable Reuse
• What Are We Waiting For?

4. Evolution of Water Reuse:
From Agricultural Reuse
to Landscape Irrigation
to Industrial Reuse
to Groundwater Recharge
to Indirect Potable Reuse
to Direct Potable Reuse

5. Crops Grown with Recycled Water
Artichokes 76% Lettuce 1.8%
Strawberries 2.3%
Broccoli 1.1% Celery
Cauliflower 4.8%
1.0%

6. Israel, Dan Region Project

7. Direct or Indirect
• Definitions
• Water Quality Differences
– Direct; Nearly Pure Water
– Indirect; Blended with Runoff, Groundwater
• Role of the Environmental Buffer
– Psychological Barrier
– Regulatory CYA
– Technological Reasons:
• Storage
• Quality Control
• Which Will It Be?

8. Successful Potable Reuse Examples
• Unplanned Potable Reuse along Major Rivers
• Windhoek
• Alexandria, Virginia
• Singapore
• Orange County Groundwater Replenishment
• Los Angeles County Seawater Intrusion Barriers
• LA, Montebello Forebay Groundwater Recharge
• El Paso, Texas
• Chanute, Kansas 1956-57
• Denver DPR Demonstration Study 1985-88

9. Failed Potable Reuse Projects
• San Diego “Repurified Water”
– Senatorial Candidate’s Populism
– “Toilet-to-Tap”
– “Effluent of the Affluent”
• City of Los Angeles “East Valley Project”
– Mayoral Candidate’s Demagoguery
– San Fernando Valley Separatist Movement
• Livermore “Pure Water Revival”
– Anti-Growth Opposition
– Disingenuous Water Quality Claims

10. Advantages of Potable Reuse
• Lower Distribution System Costs
• Higher Water Quality
– Removal of Microconstituents (aka CECs)
– Removal of Salts
– Improvement of Existing Water Sources
• Greater Reliability of Supply Resource
• Stoppage of Effluent Discharge to Environment

11. Obstacles to Potable Reuse
• Public Perception
– Alternative Supplies
– Costs
– Water Quality
– “Yuck” Factor
• Political Will
• Up-Front Costs
• Regulatory Hurdles
• “Unknowns”

12. Energy Use, kWh/AF
0 1,000 2,000 3,000 4,000 5,000
Recycled Water
Groundwater Pumping
Brackish Water Desal
Imported Water (N CA)
Ocean Water Desal
SOURCE: Inland Empire Utilities Agency

13. Cost Comparisons

16. Reverse Osmosis Cost Trends
5
4
$/cubic meter
3
2
1
0
1950 1960 1970 1980 1990 2000
Year

17. Reverse Osmosis Technology
Pathogens
Water
Bacteria
Virus
Water
Salt
Micro Reverse
Filtration Osmosis

19. Drinking Water Purified from Wastewater

20. What Are We Waiting for?
• The Right Time Is NOW!
– We Have the Technology
– The Price Is Right
– Our Mindset Is Not There Yet
• Political Will Is Lacking
• Perceptions Are Out of Touch with Reality
– Quality Is Far Better than Conventional Potable Supplies
– Public Education / Outreach Is Lacking
– Need to Get Over the Fear Factor, Yuck Factor, Unknown…
• Crisis Atmosphere Would Push Potable Reuse
– Drought (Atmospheric, Legal, Climate Change)
– Population Explosion
– Competing Demands for Water